Studies On The Growth And Feeding Characteristics Of Pseudorasbora Parva

Pseudorasbora parva is a small fish belongs to Cypriniformes, Cyprinidae, Pseudorasbora parva is widely spread as the native species in the East Asia, and now it has spread around the world. Pseudorasbora parva brings the serious influence to the ecosystem where it intrusion. So increasing with the intrusion of Pseudorasbora parva, the research on the prevention mechanism of intrusion which based on the biology characteristics were increased. The research on the pollution of water which use the Pseudorasbora parva as the indicator organism also based on the biology characteristics. 532 individuals were collected using the nets and gill nets around the Nanwan Lake which located in the upper reaches of Huaihe River in 2014 and 2015. In this study,we research on the age, growth and feeding characteristic of Pseudorasbora parva through the determination and analysis of the samples. The primary results are as follows:1. The sex ratio is 0.64:1. The range of body length is 35.82-88.28 mm with a mean body length 61.61±11.8 mm, the range of body weight is 3.07-59.17 g with a mean body weight 19.23±10.73 g. There has an significantly different between the female and male of the length and weight distribution（P<0.05）, male individual is lager than female.2. Through the comparison of scales, vertebrae, opercular, otolith for age interpretation, rings on the scales are clear and complete, scales for identification of sample age interpretation skills was 98.15%, scales are the best material on age identification of Pseudorasbora parva.3. Sex-specific relationships between body weight （W） and body length （L） were W=9.602E-5L2.928 for female is uniform growth and W=4.487E-5L3.116 for male is allometry. There are significantly different between the male and female（P<0.05）. The relationships between body length and the scale radius （R） were described using the following equations:L=16.399+0.053R for females and L=23.501+0.0414R for males. Sex-specific growth equation for female were L_t=107.005(1-e-^{0.246（t+0.76）}), W_t=84.034(l-e^{0.246（t+0.76）})^2.928; for male were L_t= 145.254(1-e^{-0.181（t+0.66）}), W_t=244.989(1-e^{-0.181（t+0.66）})^3.116. The age of growth inflexion points in female was 3.607 year with the body length 70.46 mm and body weight 24.72 g, and that in male 5.619 year with the body length 98.64 mm and body weight73.53 g.4. Pseudorasbora parva in algae as the main food in Nanwan Lake. In algae appear frequency highest Bacillariophyta 77.85 percent and zooplankton is higher weight percentages of 37.27%. Pseudorasbora parva in spring and summer with algae and aquatic plants as the main food of benthic animal in autumn and winter, eat more. The frequency of the occurrence of benthic animal in body length increased in larger individuals. Male than female parva consume more zooplankton and benthonic animal and aquatic plants and other larger food.5. Pseudorasbora parva in summer and autumn for feeding exuberant period, with higher feeding intensity and winter feeding intensity minimum, but did not appear in the jejunum. Pseudorasbora parva feeding intensity with age and the growth of body length increased, the feeding intensity of male is higher than female.